Open Access. Powered by Scholars. Published by Universities.®

Digital Commons Network

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 11 of 11

Full-Text Articles in Entire DC Network

Standard-Level Herbivory In An Old-Growth Conifer Forest Canopy, David C. Shaw, Kristina A. Ernest, H. Bruce Rinker, Margaret D. Lowman Dec 2006

Standard-Level Herbivory In An Old-Growth Conifer Forest Canopy, David C. Shaw, Kristina A. Ernest, H. Bruce Rinker, Margaret D. Lowman

All Faculty Scholarship for the College of the Sciences

Herbivory is an important ecological process in forest canopies but is difficult to measure, especially for whole stands. We used the Wind River Canopy Crane in Washington State to access 101 randomly-located sample points throughout the forest canopy. This provided a relatively quick and convenient way to estimate herbivory for a whole stand. The overall level of herbivory was estimated at 1.6% of leaf area. The distribution was strongly skewed to the lower canopy where broad-leafed species experienced higher levels of herbivory. Herbivory averaged 0.3% in conifers and 13.5% in broad-leafed species. Fully half of the sample points had no …


Distance-Based Genome Rearrangement Phylogeny, Li-San Wang, Tandy Warnow, Bernard M.E. Moret, Robert K. Jansen, Linda A. Raubeson Oct 2006

Distance-Based Genome Rearrangement Phylogeny, Li-San Wang, Tandy Warnow, Bernard M.E. Moret, Robert K. Jansen, Linda A. Raubeson

All Faculty Scholarship for the College of the Sciences

Evolution operates on whole genomes through direct rearrangements of genes, such as inversions, transpositions, and inverted transpositions, as well as through operations, such as duplications, losses, and transfers, that also affect the gene content of the genomes. Because these events are rare relative to nucleotide substitutions, gene order data offer the possibility of resolving ancient branches in the tree of life; the combination of gene order data with sequence data also has the potential to provide more robust phylogenetic reconstructions, since each can elucidate evolution at different time scales. Distance corrections greatly improve the accuracy of phylogeny reconstructions from DNA …


Perchlorate And Nitrate Remediation Efficiency And Microbial Diversity In A Containerized Wetland Bioreactor, Paula Krauter, Bill Daily Jr., Valerie Dibley, Holly Pinkart, Tina Legler Aug 2006

Perchlorate And Nitrate Remediation Efficiency And Microbial Diversity In A Containerized Wetland Bioreactor, Paula Krauter, Bill Daily Jr., Valerie Dibley, Holly Pinkart, Tina Legler

All Faculty Scholarship for the College of the Sciences

We have developed a method to remove perchlorate (14–27 μg/L) and nitrate (48 mg/L) from contaminated groundwater using a wetland bioreactor. The bioreactor has operated continuously in a remote field location for more than 2 yr with a stable ecosystem of indigenous organisms. This study assesses the bioreactor for long-term perchlorate and nitrate remediation by evaluating influent and effluent groundwater for oxidation-reduction conditions and nitrate and perchlorate concentrations. Total community DNA was extracted and purified from 10-g sediment samples retrieved from vertical coring of the bioreactor during winter. Analysis by denaturing gradient gel electrophoresis of short, 16S rDNA, polymerase-chain-reaction products …


Photoreductive Dissolution Of Ferrihydrite By Methanesulfinic Acid: Evidence Of A Direct Link Between Dimethylsulfide And Iron-Bioavailability, Anne M. Johansen, Jennifer M. Key Jul 2006

Photoreductive Dissolution Of Ferrihydrite By Methanesulfinic Acid: Evidence Of A Direct Link Between Dimethylsulfide And Iron-Bioavailability, Anne M. Johansen, Jennifer M. Key

All Faculty Scholarship for the College of the Sciences

Within open‐ocean regions where excess macronutrients are present, phytoplankton growth is limited by the bioavailability of iron supplied to these areas primarily within atmospheric aerosols of crustal origin. However, processes that control the abundance of biologically accessible iron in these aerosols are largely unknown. Here we show that dissolution of ferrihydrite, a surrogate iron(oxy)hydroxide phase found in atmospheric waters, is enhanced in the presence of methanesulfinic acid (MSIA, CH3SO2H, a dimethylsulfide (DMS) oxidation intermediate) in laboratory irradiation experiments with aqueous suspensions that simulate marine aerosol particles. The increased release of soluble Fe(II) is attributed to a …


The Effect Of Male Competition On Female Choice In Brandt’S Vole, Lasiopodomys Brandti, Jianjun Zhang, Dazhao Shi, Lixing Sun Jun 2006

The Effect Of Male Competition On Female Choice In Brandt’S Vole, Lasiopodomys Brandti, Jianjun Zhang, Dazhao Shi, Lixing Sun

All Faculty Scholarship for the College of the Sciences

The effect of male competition on female choice in the Brandt’s vole (Lasiopodomys brandti) was studied in the laboratory. Using a two-way choice test, we showed that when males did not compete, estrous females preferred and mated with the dominant males, but non-estrous females preferred subordinate males. However, when males competed, all dominant males gained the priority to mate, and the amicable behaviour between males, regardless of their dominant status, and between non-estrous females increased, compared with the behaviour between males and the estrous females. These results showed that interactions among Brandt’s voles were not only influenced by …


Carrier Dynamics In Α‐Fe2o3 (0001) Thin Films And Single Crystals Probed By Femtosecond Transient Absorption And Reflectivity, Alan G. Joly, Joshua R. Williams, Scott A. Chambers, Gang Xiong, Wayne P. Hess, David M. Laman Mar 2006

Carrier Dynamics In Α‐Fe2o3 (0001) Thin Films And Single Crystals Probed By Femtosecond Transient Absorption And Reflectivity, Alan G. Joly, Joshua R. Williams, Scott A. Chambers, Gang Xiong, Wayne P. Hess, David M. Laman

All Faculty Scholarship for the College of the Sciences

Femtosecond transient reflectivity and absorption are used to measure the carrier lifetimes in α‐Fe2O3 thin films and single crystals. The results from the thin films show that initially excited hot electrons relax to the band edge within 300 fs and then recombine with holes or trap within 5 ps. The trapped electrons have a lifetime of hundreds of picoseconds. Transient reflectivity measurements from hematite (α‐Fe2O3)single crystals show similar but slightly faster dynamics leading to the conclusion that the short carrier lifetimes in these materials are due primarily to trapping to Fe d- …


Serial Ruptures Of The San Andreas Fault, Carrizo Plain, California, Revealed By Three-Dimensional Excavations, Jing Liu-Zeng, Yann Klinger, Kerry Sieh, Charles Rubin, Gordon Seitz Feb 2006

Serial Ruptures Of The San Andreas Fault, Carrizo Plain, California, Revealed By Three-Dimensional Excavations, Jing Liu-Zeng, Yann Klinger, Kerry Sieh, Charles Rubin, Gordon Seitz

All Faculty Scholarship for the College of the Sciences

It is poorly known if fault slip repeats regularly through many earthquake cycles. Well‐documented measurements of successive slips rarely span more than three earthquake cycles. In this paper, we present evidence of six sequential offsets across the San Andreas fault at a site in the Carrizo Plain, using stream channels as piercing lines. We opened a latticework of trenches across the offset channels on both sides of the fault to expose their subsurface stratigraphy. We can correlate the channels across the fault on the basis of their elevations, shapes, stratigraphy, and ages. The three‐dimensional excavations allow us to locate accurately …


Geochronology And Tectonic Significance Of Middle Proterozoic Granitic Orthogneiss, North Qaidam Hp/Uhp Terrane, Western China, Chris G. Mattinson, Joseph L. Wooden, Juhn G. Liou, D. K. Bird, C. L. Wu Jan 2006

Geochronology And Tectonic Significance Of Middle Proterozoic Granitic Orthogneiss, North Qaidam Hp/Uhp Terrane, Western China, Chris G. Mattinson, Joseph L. Wooden, Juhn G. Liou, D. K. Bird, C. L. Wu

All Faculty Scholarship for the College of the Sciences

Amphibolite-facies para- and orthogneisses near Dulan, in the southeast part of the North Qaidam terrane, enclose minor ultra-high pressure (UHP) eclogite and peridotite. Field relations and coesite inclusions in zircons from paragneiss suggest that felsic, mafic, and ultramafic rocks all experienced UHP metamorphism and a common amphibolite-facies retrogression. Ion microprobe U–Pb and REE analyses of zircons from two granitic orthogneisses indicate magmatic crystallization at 927 ± Ma and 921 ± 7 Ma. Zircon rims in one of these samples yield younger ages (397–618 Ma) compatible with partial zircon recrystallization during in-situ Ordovician-Silurian eclogite-facies metamorphism previously determined from eclogite and paragneiss …


Pyritized Tube Feet In A Protasterid Ophiuroid From The Upper Ordovician Of Kentucky, U.S.A., Alexander Glass Jan 2006

Pyritized Tube Feet In A Protasterid Ophiuroid From The Upper Ordovician Of Kentucky, U.S.A., Alexander Glass

All Faculty Scholarship for the College of the Sciences

A single specimen of the protasterid ophiuroid Protasterina flexuosa from the Kope Formation (Cincinnatian, Upper Ordovician) of Kentucky exhibits three−dimensionally pyritized tube feet. This represents the first report of soft−tissue preservation in an echinoderm from the type−Cincinnatian series. The tube feet are solid and lack all internal structure. They consist of aggregated masses of small euhedral to subhedral pyrite crystals suggesting that pyritization, although decay−induced and mediated, did not necessarily replicate soft−tissues but might instead have formed inside the void−spaces left behind during the decay process. The discovery of pyritized soft−tissue as delicate as ophiuroid tube feet suggests that similar …


Writing Projective Representations Over Subfields, Stephen P. Glasby, C. R. Leedham-Green, E. A. O'Brien Jan 2006

Writing Projective Representations Over Subfields, Stephen P. Glasby, C. R. Leedham-Green, E. A. O'Brien

All Faculty Scholarship for the College of the Sciences

Let G=〈X〉be an absolutely irreducible subgroup of GL(d, K), and let F be a proper subfield of the finite field K. We present a practical algorithm to decide constructively whether or not G is conjugate to a subgroup of GL(d, F).K×, where K× denotes the centre of GL(d, K). If the derived group of G also acts absolutely irreducibly, then the algorithm is Las Vegas and costs O(|X|d3+d2log|F|) arithmetic operations in K. This work forms part of a recognition project based on Aschbacher’s classification of maximal subgroups of GL(d, K).


Dynamical Volatilities For Yen-Dollar Exchange Rates, Kyungsik Kim, Seong-Min Yoon, C. Christopher Lee, Myung-Kul Yum Jan 2006

Dynamical Volatilities For Yen-Dollar Exchange Rates, Kyungsik Kim, Seong-Min Yoon, C. Christopher Lee, Myung-Kul Yum

All Faculty Scholarship for the College of the Sciences

We study the continuous time random walk theory from financial tick data of the yen-dollar exchange rate transacted at the Japanese financial market. The dynamical behavior of returns and volatilities in this case is particularly treated at the long-time limit. We find that the volatility for prices shows a power-law with anomalous scaling exponent κ = 0.96 (one minute) and 0.86 (ten minutes), and that our behavior occurs in the subdiffusive process. Our result presented will be compared with that of recent numerical calculations.